Avx Corporation

Gang Ning

Bharat Rawal

Zebbie Lynn Sebald

Brady A Jones

James Allen Fife

Stanislav Zednicek

Zdenek Sita

Dirk H Dreissig

James Steven Bates

Robert Hazen Pease

Lee Shinaberger

Bob Knopsnyder

Jessica M Smith

A capacitor assembly that includes a conductive polymer electrolytic capacitor that is enclosed and hermetically sealed within a ceramic housing in the presence of an inert gas is provided. Without intending to be limited by theory, the present inventors believe that the ceramic housing is capable of limiting the amount of oxygen and moisture supplied to the conductive polymer of the capacitor. In this manner, the conductive polymer is less likely to oxidize in high temperature environments, thus increasing the thermal stability of the capacitor assembly.

Hermetically sealed capacitor assembly

A capacitor containing an electrochemical cell that includes ruthenium oxide electrodes and an aqueous electrolyte containing a polyprotic acid (e.g., sulfuric acid) is provided. More specifically, the electrodes each contain a substrate that is coated with a metal oxide film formed from a combination of ruthenium oxide and inorganic oxide particles (e.g., alumina, silica, etc.). Without intending to be limited by theory, it is believed that the inorganic oxide particles may enhance proton transfer (e.g., proton generation) in the aqueous electrolyte to form hydrated inorganic oxide complexes (e.g., [Al(HO)] to [Al(HO)(OH)]). The inorganic oxide thus acts as a catalyst to both absorb and reversibly cleave water into protons and molecular bonded hydroxyl bridges. Because the anions (e.g., sulfate and bisulfate ions) in the electrolyte are not bound in the coordination sphere of the formed aqua complexes, they do not impede the condensation of these complexes required to achieve the additional capacitance over the potential range. As a result, the ionic charges are kept separate and the chemical process may generate pseudo-capacitance. This, in turn, may result in an increase in the charge density and capacitance of the electrode.

Electrochemical capacitor containing ruthenium oxide electrodes

A porous substrate for use in a wide variety of applications, such as wet capacitors, is provided. The substrate is formed by subjecting a metal substrate to a voltage while in solution to initiate anodic formation of an oxide film. Contrary to conventional anodization processes, however, the newly created oxide quickly breaks down to once again expose the metal surface to the electrolytic solution. This may be accomplished in a variety of ways, such as by raising the voltage of the solution above a critical level known as the 'breakdown voltage', employing a corrosive acid in the solution that dissolves the oxide, etc. Regardless of the mechanism employed, the nearly simultaneous process of oxide growth/breakdown results in the formation of a structure having pores arranged at substantially regular intervals. The resulting structure is highly porous and can exhibit excellent adhesion to electrochemically-active materials and stability in aqueous electrolytes.

Substrate for use in wet capacitors

A wet electrolytic capacitor that includes a plurality of anodes, cathode, and working electrolyte that is disposed in electrical contact with the anodes and current collector is provided. Any number of anodes may generally be employed, such as from 2 to 40, in some embodiments from 3 to 30, and in some embodiments, from 4 to 20. The anodes are thin and typically have a thickness of about 1500 micrometers or less, in some embodiments about 1000 micrometers or less, and in some embodiments, from about 50 to about 500 micrometers. By employing a plurality of anodes that are relatively thin in nature, the resulting wet electrolytic capacitor is able to achieve excellent electrical properties. For example, the equivalent series resistance ('ESR')&#x2014;the extent that the capacitor acts like a resistor when charging and discharging in an electronic circuit&#x2014;may be less than about 1500 milliohms, in some embodiments less than about 1000 milliohms, and in some embodiments, less than about 500 milliohms, measured with a 2-volt bias and 1-volt signal at a frequency of 1000 Hz.

Wet electrolytic capacitor containing a plurality of thin powder-formed anodes

A wet electrolytic capacitor that comprises an anode, cathode, and working electrolyte is provided. The cathode contains a coating disposed over a surface of a current collector, wherein the coating comprises a plurality of electrochemically-active particles and a binder. The binder is formed from an amorphous polymer having a glass transition temperature of about 100&#xb0; C. or more.

Cathode coating for a wet electrolytic capacitor

A wet electrolytic capacitor that includes an anode, cathode, and an electrolyte is provided. The cathode contains a substrate and a coating overlying the substrate. The coating comprises a sintered body containing carbonaceous particles (e.g., activated carbon) and inorganic particles (e.g., NbO).

Wet electrolytic capacitor containing a cathode coating

A wet electrolytic capacitor that includes an anode, cathode, and an electrolyte is provided. The cathode contains a plurality of metal particles disposed on a surface of a substrate and sinter bonded thereto. The metal particles have a median size of from about 20 to about 500 micrometers.

Wet electrolytic capacitor

A working electrolyte for use in a wet electrolytic capacitor is provided. The electrolyte is relatively neutral and has a pH of from about 5.0 to about 8.0, in some embodiments from about 5.5 to about 7.5, and in some embodiments, from about 6.0 to about 7.5. Despite possessing a neutral pH level, the electrolyte is nevertheless electrically conductive. For instance, the electrolyte may have an electrical conductivity of about 10 milliSiemens per centimeter ('mS/cm') or more, in some embodiments about 30 mS/cm or more, and in some embodiments, from about 40 mS/cm to about 100 mS/cm, determined at a temperature of 25&#xb0; C.

Neutral electrolyte for a wet electrolytic capacitor

A wet electrolytic capacitor that includes an anode, cathode, and a liquid electrolyte disposed therebetween is provided. The cathode contains a metal oxide coating, such as NbO, in conjunction with other optional coatings to impart improved properties to the capacitor.

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Myrtle Beach, SC, United States of America

Gang Ning